Antenna system



Aug. 171, 1943.y A

-LQ A. GE'BHAR'D -ETAL ANTENNA sys-TEM original Filed MairQhll, 195o 2 sheets-Sheet 1 'Affair/v?? `2 Sheets-Sheet 2- ANTENNAV SYS TEM LA.- GEBHARD Erm.

original Filed March 11, 1930 Aug-$17, 1943.

`Reissued Aug. 17, 1943 ANTENNA SYSTEM Louis A. Gebhard and Raymond B. Meyer,

Washington, D. C.

Original No. 1,903,811, dated April 18, 1933, Serial No. 434,882, March 11, 1930. Application for reissue May 11, 1943, Serial No. 486,604

(Cl. Z50-33) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 6 Claims.

The invention described herein may be manufactured and-used by or for the Government for governmental purposes without the payment to us of any royalty thereon.

Our invention relates broadly to high frequency radio communication systems :and more particularly to the construction of an antenna system for high frequency communication.

One ofthe objects of our invention is to provide a construction of antenna-system for high frequency Vradio communication systems which may be accurately adjusted for operation at a selected high frequency.

Another object of our invention is to provide a construction of antenna system which'maybe readily set or reset for operation at any -'selected high frequency for securing high efficiency in the operation of radio communication syst=ems. e

A further object of our invention is to provide an antenna system of variable capacity for communication at extremely high frequencies with mechanical means for accurately fixing the capacity of the antenna for operation at a selected high frequency.

Still another object of our invention is to pro vide a construction'of high frequency antenna which is readily adjustable with respect to `the frame of a transmitter on which the antenna transmitter with may lbe `mounted, means being provided on the t transmitter for indicating the effective extension mitter of our invention and showing the means which We employ for the projection of the' antenna through the transmitter; Fig. 3 is a crosssectional viewthrough the control means for effecting adjustment of the antenna taken on line 3 4 of Fig. 2; Fig. 4 is avertical cross-sectional `viewl through 4the transmitting antenna and showing a. fragmentary part of the control means therefor; and Fig'. 5 is a schematic view showing the transmitting antennaJ of our invention'in associatlon with a transmitter circuit.

Our invention is ldirected to an antenna system for operation at extremely high frequencies.

to an effective length which is proportional to the frequencies at which the transmitter operates.I For compact assembly of the transmitting apparatus with respect to the antenna system, we mount the antenna directly in the -frame of the control means extending through the front panel `of -the transmitter for adjusting the antenna to a particular length. We provide a counter mechanism by which the antenna may be extended to a selec-ted length for transmissionupon a given frequency and returned to the same setting when it is desired to transmit at that selected frequency. The antenna construction of our invention is extremely equipped with a high frequency antenna system y according t-o our invention, The panel I6 of the transmitterris shown at I6 through which a control crank I4 projects for elevating or lowering the antenna while observing readings of thecounter Il through a sight open in the panel I6 of the transmitter. by tubular members 4 and 5 which project through the aperture 2l) in the top of the transmitter whchis electrically shielded at 36 and on al1 sides thereof. The antenna is Imounted upon a support 3 by means ofthe collar I2,

i which is secured on support 3" by means of bolt shown.

I2a which eXtend'therethrough as v The metal tube orI cylinder l is screw threaded intol the collar I2 in such manner that tube l is erected vertically with respect to the members support 3. A bearing E is mounted interiorly of the tube I and provides a snug sliding fit within tube 4. The center'ofy the bearing 6 is screw threaded as indicated at 6a so that the bearing 6 may be positively driven upward and outward inaccordance with the rotation o! the drive shaft 1. A 'thrustcollar I3 is secured tothe shaft 'I to provide va support and bearing for the interior members of the antenna system. The upper end of shaft 1 is provided with a collar In which provides an additional support between the inner tubular member 5 and the shaft 1-. A

bevel gear 2 is secured to the lower end of the shaft] after itpasses through the support 3. Bevel gear I isprovided in engagement with the bevel gear 2 for moving bevel gear 2 in accordance with the operation of shaft I I, which con- The antenna is constituted length of the antenna.

.sides of the tubular member 4.

of shaft Il causes tube to slidewlthin tube 4 thus'providing a means of adjusting the eiective length of the antenna while the transmitter is in operation. A pin 9 is secured through tube 4 adjacent its upper end and extends far enough v Vinto tube 5 so as to engage the longitudinally extending slot 8 therein. This slot 8 extends to. within a short distance of each end of the inner tubular member 5. The purpose of the pin 9 and slot 8 is to prevent tube 5 from turning around within tube 4 when the gearing mechanism is actuated. The dimensions of tubes 4 and 5 and of shaft 1 may be' of any desired length and diameter, while the ratio existing between gears Il and 2 and pitch of the thread on 'I may be chosen to give any desired speed of adjustment to the Fig.' 5 shows a high frequency oscillator provided with our adjustable antenna. The antenna may form an integral part of the trans-` mitter or may `be coupled thereto by means of a radio frequency transmission line. The use of such an antenna permits the antenna to be tuned while poweris on the transmitter and enables the length of thel ante'nna to 1 be adjusted with great accuracy. The` antenna is rigid and thus retains its constants once the proper adjustment is arrived at, a condi-- tion which is necessary at extremely high frequencies. v.insulating shaft II is operated by means of crank I4 through shaft I5. This shaft I-5 may be supported in a bearing in the front panel IB of the radio transmitter. A counter I1 is provided connected to shaft I5 by means of bevel gears IB and I9. A window in the front panel I8 permits sighting the dial of the 'counter I1. This indicating mechanism affords a means of resetting any, particular adjustment of the antenna. In order to provide .erally by reference .character 23 as including grid, cathode .and plate electrode. The cathode circuits is heated from an alternating current source and supplied to the cathode from transformer 25. The potential for the plate is supplied from generator 26 while biasing potential for the grid of tube 23 is supplied from generator 21. The keying circuit for the transmitter has been shown at 28. The -connection from the oscillator system is taken from the base 'of the tubular member 24 through the conductor 30 terminating. at one of the securing .bolts which wehave indicated at I2a.. In order to mechanically steady the 'transmitting antenna we provide an insulated yoke member 3i extended across the aperture 2li in the top of the transmitter 4and embracing the The base of the tubular member 4 is anchored by bolts Ila at such a distancebelow the top oi' the transmitter that the center of gravity ofthe antenna ismaintained low so that when the antenna is fully projected there is, no tendency for the equilibrium of the transmitter to be upset. 'I'he supporting plate I formed from insulation masists of ahigh frequency insulator. The turning terial is mounted on panel members 32 extending laterally of the transmitter to which the insulated supportingplate 3 is fastened by means of bolts 33. A bracket 34 depends from insulated 5 supporting plate 3 and provides a bearing for shaft Ii. When the transmitter is not in use the telescopic sections may be collapsed one with respect to the other thereby housing the antenna substantially within the transmitter as Vrepresented in Fig. 2. -The end ca'p 35 closes -the upper end of tubular member 5.

Our invention is directed to an electrically live adjustable antenna element as distinguished from a mechanical supporting mast which is electrically dead. Such mechanical supporting masts have served' only as mechanical supports for antenna. wires and are not electrically live antenna elements as embodied in our invention. We provide means extending through the telescopic sections of the electrically live antenna element and operative from a remote position by control means for extending and retracting the telescopic sections with respect to each other for adjusting their eifective electrical capacity. The said control means is insulated from the means V4for extending a'nd retracting the telescopic sections so that extraneous capacity effects are not introduced when adjusting the antenna system.

We have successfully used the transmitting antenna of our invention for transmission over a range of 30,000 to 75,000 kilocycles for which the construction of antenna herein has been found to be particularly emcient. but we de- 35 sire it to be understood that modifications may be made and that no limitations upon our in` vention are intended other than are imposed by the scope of the appended claims.

' What we claim as new and desire to secure 40 by .Letters Patent of the United States is as follows:

1. In a radio communication system, an electrically live adjustable antenna element comprising a multiplicityof tubular sections telescopically disposed one with respect to another, means for insulatingly supporting said antenna element adjacent the base thereof,A an electrical connection for radio communicationapparatus adjacent the base of said antenna element, means extending axially through said sections for controlling the projection and collapse of said sections with electrically live tubular member telescopically positioned within said aforementioned tubularl member. means extending through said tubular `members for shifting one tubular member with insulated support. gear means mounted adjacent said insulated support,V control means connected with said gear means remote from said antenna system for extending and retracting one tubular member with respect to the tubular member erected upon said insulated support, and connecting means adjacent the base of said first mentioned electrically live tubular member for establishing electrical connection with radio communication apparatus.

erected upon said insulated support, a second respect to the tubular member erected upon said I I3. In a high frequency antenna. system, a

transmitter frame, a radiating antenna element projectible through said transmitter frame and sections disposed telescopically one with respect to another,v screw means extending through said tubular sections for extending or retracting said tubular sections telescopically, a gear carried by said screw means, a .control driving gear mounted to actuate said first mentioned gear for controlling the extension of said tubular sections. and an insulated control shaft mounted to actuate said driving gear and projecting outside said transmitter frame. whereby the extension of said tubular sections may be manually adjusted from the exterior of said transmitter frame whileJ said transmitter is operating at high voltages.

5. An antenna system comprising an insulated supportl an electrically live tubular member mounted on said insulated support, a second electrically live tubular member telescopically slidable with the surface thereof in continuous electrical contact with the surface of said ilrst mentioned electrically live tubular member, means extending axially with respect to' said 3 support and through said tubular members for shifting one tubular member with respectrto the .comprising a multiplicity of conductive tubular tubular member carried by said insulated support, means mounted adjacent said insulated support and controlledremotely therefrom for operating said first mentioned means for extending and retracting one tubular member with respect to the tubular member mounted `upon said insulated support, and radio frequency connecting means extending from a position adjacent the base of said first mentioned electrically live tubular member for establishing electrical connection with radio communication apparatus;

6. In a radio communication system, an electrically live adjustable antenna element comprisinga multiplicity oi'V tubular sections telescopically disposed one with respect tor another, means l for' insulatingly supporting said antenna element adjacent the base thereof, an electrical shield ex` tending adjacent the base of the antenna element and the supporting means therefor, an electrical connection for radio communication apparatus adjacent the base of said antenna element, means extending axially through said sections for'controlling the projection andv collapse of said sections with respect to each other in special relation to said electrical shield, and means electrically insulated from said second mentioned means for adjusting said second mentioned means from a remote position for correspondvingljr controlling the amount of overlap of the sections with respect to each otherand with respect to said electrical shield.

LOUIS` A.' GEB ,RAYMOND Bam 

